Promoters of city-based GreenSignal Bio Pharma Ltd. (GSBPL), a vaccine manufacturing company, have decided to dilute their holdings in the company through an offer-for-sale. The company, headed by N. Gopalaswami, former Chief Election Commissioner of India, has already filed the draft red herring prospectus with the Securities and Exchange Board of India (SEBI). The offer-for-sale will constitute about 1,45,79,560 shares of face value of Rs.10 each at a premium, to be decided through the book-building route. This will see the promoters offering 38 per cent of their holdings to qualified institutional bidders, high net worth individuals and retail investors in India as well as eligible foreign institutional investors, foreign portfolio investors and non-resident Indians.